1. Field of the Invention
The present invention provides an improved casting alloy for use in costume jewelry and jewelry samples.
2. Prior Art
Gold is generally alloyed with other metals for such use and requires a relatively low melting point. The alloys must be moldable and castable with a low surface tension to permit conformance to intricate molds. Such alloys should provide a material which does not easily corrode or tarnish, especially when used in jewelry.
It is basic that gold is one of the most valuable metals, and the look of gold is a highly desired characteristic of any metal alloy.
In accordance with this invention, an alloy is provided which contains no gold, and yet which provides an alloy material that polishes, works and looks like gold. Also, the alloy of this invention can be tarnish and corrosion resistant in the manner of gold in an ammonia or chlorine solution.
The alloy of this invention may resemble 14 carat gold in color and be highly corrosion resistant equal or superior to lower gold alloys, even though the alloy of this invention has zero percent gold in the preferred embodiment.
In attempts of the prior art to develop a metal alloy possessing the true color of gold, while maintaining its capabilities of being readily workable and polished, various non-precious metals and gold have been tried. For example, the present applicant's U.S. Pat. No. 4,350,527 is directed to a gold colored alloy, having zero to ten percent gold content with seven to twenty percent copper, fifteen to twenty percent indium, and five to fifteen percent palladium. The alloy of '527 teaches zero to ten percent gold. However, '527 requires the use of silver, and does not disclose the unexpected marked increase in gold color caused by the combination of a high percentage of copper in the presence of nickel.